Ram jet with steam augmentation



P 1953 G. F. LANDGRAF RAM JET WITH STEAM AUGMENTATION Filed April 24, 1946 NEE/04m Jrwenior Patented Apr. 21, 1953 UNITED STATES PATENT OFFICE RAM JET WITH STEAM AUGMENTATION George Frederick Landgraf, Cockeysville, Md.

Application April 24, 1946, Serial No. 664,533

(Cl. (SO-35.6)

4 Claims.

This invention relates to an improved power plant utilizing the reactive thrust of emittant high velocity gases.

As is known, while the principle of jet propulsion has been spectacularly invoked during the war in the construction of jet propelled planes, for example, the fundamental principle of reactive thrust has long been known. Such jet power plants involve essentially the exceedingly rapid heating and consequent expansion of a gas which escapes through an orifice or jet such that the gas pressure is exerted on the outlet or jet thus exerting a reactive thrust on the unit carrying the combustion chamber.

In modern jet propelled units as, for example in a jet propelled airplane, air is forced into an air compression chamber by a high speed impeller driven by a shaft from a turbine wheel. The air is heated to exceedingly high temperatures producing immediate, tremendous expansion which provides the driving thrust.

In such constructions one of the complicating factors has been the necessity of utilizing air compression units of considerable size in order to insur maximum compression and provide the desired volume of air. Another limitation in construction derives from the high temperatures which are desired. These are necessarily limited by the heat resistance of the alloy steels used in the construction.

It has now been found-that jet propulsion motors may be constructed which are eminently simple and operate effectively with minimum mechanical blower or air compression capacity and with reduced combustion temperatures. Considered broadly, the invention comprehends the concept of utilizing a steam generating unit in a jet motor and so correlating such unit with the motor that an effective coolant action is secured coupled with an improved air feed.

In order to enable a more ready comprehen sion of the invention an illustration of the essential units of the improved power plant is shown in the accompanying drawing in which:

Fig. 1 is a diagrammatic longitudinal section of a jet motor illustrating the cooperative relationship of the steam generating unit with the other elements of the motor, .and

Fig. 2 is a cross-section taken on line 2.32 of Fig. 1.

In order to simplify the description of .the in.- vention the structure shown in the drawing has been reduced to illustrateonly the essential features of the invention. As will be pointed not subsequently the commercial unit may be-asso- 2 ciated with a suitable steam turbine to produce mechanical power from the jetted high velocity gases which power may be utilized for whatever purpose desired.

As shown in the drawings the motor comprises essentially a casing l which serves as a combustion chamber. This is constructed of any suitable heat resistant alloy. The casing is extended to form a tapered chamber 2 which terminates in the open jet nozzle 3. The end of the combustion chamber opposite the tapered jet xtension is shown in the drawings as broken away. It will be understood that such end comprises the air intake into the combustion chamer and that such air may be forced into the chamber by any suitable blower, compressor or the like.

Liquid fuel fed into the combustion chamber through fuel line 4 and thence through the injector 5. In operation a cheap liquid fuel such as kerosene, gas oil or the like, is continuously fed into the combustion zone and is there ignited by a suitable means such as the appropriately located spark gas igniter 6.

I-n jet motor constructions employed heretofore the heated and expanded air in admixture with the products of coniliustion were passed through the jet nozzle to develop the reactive thrust. In som constructions these gases were utilized in transit to the orifice to drive turbine blades or impellers the power from which was utilized for sundry purposes as, for example to operate an air compressoror blower which latter feeds air to the combustion chamber.

In accordance with the present invention the high temperatures and high velocity gases discharged from the combustion chamber are utilized to generate steam which generated steam escapes through a jet orifice aligned or coaxial with the main jet orifice. As shown, a steam chamber 1 is mounted in the extension 2 by means of the elongated fins;8. Thesteam chamber and fins are constructed of suitable heat resistant alloy steel to withstand the tempera- ,tures involved. The preferably are welded to the steam chamberand to the main casing 2. The fins thus serve the double function of supporting the steam chamber and of facilitating the conduction of heat from the hot gases to the interior of the chamber. The steam chamber, as will be noted,-is of stream-lined form so as to minimize as much, as ossible its resistance to the flow of the hot expanded air and combustion gases while providing adequate surface heating areas for the chamber. If desired, also the fins 8 may be filleted, as at 9, at the joints between the steam chamber on the one hand, and casing 2 on the other, to further reduce the resistance and to avoid interference and burbling.

The steam chamber is supplied with water in any suitable manner as, for example through the water injector line [8. It will be seen that the stream-lined steam chamber is coaxial with the casing and its discharge orifice is coaxial with the main jet orifice 3. In these circumstances when it is brought up to temperature the steam generator acts as a fiash boiler, the heat for steam generation being derived from the exhaust gases from the combustion chamber and in such a manner as not to materially diminish the velocity of such gases nor, consequently, substantially decrease the reactive thrust at the jet nozzle.

The operation of the improved structure will have been appreciated from the foregoing description. In starting the unit air is forced into the combustion chamber 1 through the air intake end I by any suitable means such as a blower, compressor or the like (as shown). In the combustion chamber the air is intimately mixed with atomized fuel. The atomized fuel i ignited by means of igniter 6. The heated expanded air and combustion gases pass over the steam chamber 1 through the passages formed by the fins 8 and are discharged through the jet nozzles 3. After a very brief period the steam chamber becomes sufiiciently hot to function as a flash boiler. The water which is continuously fed to the chamber through line is immediately transformed into steam which is ejected through the steam orifice at high velocity.

It will be observed that the steam chamber is so associated withthe air intake, combustion chamber and jet orifice as to subserve a number of particularly valuable functions. The high velocity steam escaping from the steam orifice, as previously pointed out, exerts power on the outlet and thus positively contributes a reactive thrust to the jet unit. Such passage of high velocity steam through the steam orifice also functions to reduce the pressure around such orifice and thus establishes an aspirating effect drawing combustion gases and heated expanded air through the combustion chamber and heat conductor fins.

The ejected steam mixed with expanded air and the products of combustion pass at high velocity through the jet nozzle 3. This injection action is of salient importance for when the steam chamber is up to temperature, as described, the injection action is of such magnitude that it is no longer necessary to force air into the air intake by positive pressure from a blower. The injector action inspirates all the air that is necessary and hence the blower may be disconnected from its source of power.

While the described utilization of a steam generating unit with the jet motor will tend to reduce combustion temperatures thi is not reflected in a material sacrifice of efficiency for the reason that the heat so abstracted is positively employed in the development of energy, through the formation of steam which contributes to the velocity and mass of the jet emission.

It is apparent that the high velocity gases and steam emitted from the jet nozzle may be utilized to develop mechanical power for any desired purpose.

Jet propulsion units embodying the described coordinated derivative of reactive thrust from heated expanded air plus combustion products and steam generated in situ, may be utilized in a Wide variety of structures when the advantages of efiicient jet propulsion are desired such, for example as jet propelled planes, trains and automotive vehicles, rockets and the like.

. While a particular embodiment of the inven tion has been described it is to be understood that this is given didactically to exemplify the underlying principles involved and not as limiting the useful scope of the invention to the particular illustrative embodiment.

I claim:

I. A jet propulsion apparatus comprising, a combustion chamber, means to force a large v'ol ume of air into the combustion chamber, means to highly heat and expand the air in the chamber, an elongated tapered discharge passageway connected with the chamber and terminating in a jet nozzle, an elongated tapered steam generating unit axially located in the passageway and spaced equidistantly from the walls of the passageway and having a discharge orifice axially aligned with but spaced a short distance from the jet nozzle whereby steam is generated by indirect heat exchange with hot products from the combustion chamber and all the generated steam is ejected coaxially with the said products from the combustion chamber and adjacent the discharge end of the jet nozzle.

2. A jet propulsion apparatus comprising, a combustion chamber, means to feed a large volume of air into the combustion chamber, means to highly heat and expand the air in the chamber, an elongated tapered discharge passageway connected with the chamber and terminating in a jet nozzle, an elongated tapered steam generating unit of stream-lined form axially located in the passageway and having a discharge orifice axially aligned with but forwardly spaced from the jet nozzle whereby steam is generated by indirect heat exchange with hot products from the combustion chamber and all the generated steam is ejected coaxially with the said products from the combustion chamber.

3. A jet propulsion apparatus comprising, a combustion chamber, means to feed a large volume of air to the combustion chamber, means to highly heat and expand the air in the chamber, an elongated tapered discharge passageway connected with the chamber and terminating in a jet nozzle, an elongated tapered steam generating unit axially located Within the passageway and spaced from the walls of said passageway, heat conductive fins attached to the generating unit and contacting the walls of the passageway to support the generating unit in the passageway, a steam orifice connected with the steam generating unit, such orifice being spaced forwardly from and coaxially with the said jet nozzle whereby generated steam which is ejected into the passageway supplements the reactive thrust of the gases from the combustion chamber and facilitates the flow of such gases by an aspirating action.

4. A jet propulsion apparatus comprising, a combustion chamber, means to feed air to the combustion chamber, means to highly heat and expand the air in the chamber, an elongated tapered discharge passageway connected with the chamber and terminating in a jet nozzle, an elongated tapered steam generating unit axially of stream-lined form located within the passageway and spaced from the walls of said passageway, heat conductive fins attached to the generat ing unit and contacting the walls of the passage- Way to support the generating unit in the passageway, a steam orifice connected with the steam generating unit, such orifice being spaced from and coaxially with the said jet nozzle whereby generated steam ejected into the passageway supplements the reactive thrust of the gases from the combustion chamber and facilitates the flow of such gases by an aspirating action.

GEORGE FREDERICK LANDGRAF.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Gassett Aug. 25, 1885 Number 

